Influence of conventional and extended CT scale range on quantification of Hounsfield units of medical implants and metallic objects

2018 ◽  
Vol 85 (5) ◽  
pp. 343-350 ◽  
Author(s):  
Zehra Ese ◽  
Marcel Kressmann ◽  
Jakob Kreutner ◽  
Gregor Schaefers ◽  
Daniel Erni ◽  
...  
Keyword(s):  
Artifact Reduction ◽  
Metal Artifact Reduction ◽  
Metallic Materials ◽  
Dose Calculations ◽  
Medical Implants ◽  
Hounsfield Units ◽  
Implantable Medical Devices ◽  
Cardioverter Defibrillator ◽  
Accurate Dose ◽  
Scale Range

Abstract We report on the suitability of two different ranges of Hounsfield units (HU) in computed tomography (CT) for the quantification of metallic components of active implantable medical devices (AIMD). The conventional Hounsfield units (CHU) range, which is traditionally used in radiology, is well suited for tissue but suspected inappropriate for metallic materials. Precise HU values are notably beneficial in radiotherapy (RT) for accurate dose calculations, thus for the safety of patient carrying implants. Some of today’s CT machines offers an extended Hounsfield units (EHU) range. This study presents CT acquisitions of a water phantom containing various metallic discs and an implantable-cardioverter defibrillator (IPG). We show that the comparison of HU values at EHU and CHU ranges clearly reveals the superiority and accuracy of EHU. Some geometrical discrepancies perpendicular to slices are observed. At EHU metal artifact reduction algorithms (MAR) underestimates HU values rendering MAR potentially inappropriate for RT.

MR Imaging with Metal Artifact Reduction to Differentiate between Patients with and without Infected Total Hip Arthroplasty

2018 ◽  
Author(s):  
Benedikt Schwaiger ◽  
Alexandra Gersing ◽  
Daniela Muenzel ◽  
Julia Dangelmaier ◽  
Peter Prodinger ◽  
...  
Keyword(s):  
Total Hip Arthroplasty ◽  
Mr Imaging ◽  
Hip Arthroplasty ◽  
Artifact Reduction ◽  
Metal Artifact ◽  
Metal Artifact Reduction ◽  
Total Hip

Comparison of metal artifact reduction techniques in magnetic resonance imaging of carbon-reinforced PEEK and titanium spinal implants

2021 ◽  
pp. 028418512110290
Author(s):  
Georg Osterhoff ◽  
Florian A Huber ◽  
Laura C Graf ◽  
Ferdinand Erdlen ◽  
Hans-Christoph Pape ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Pedicle Screws ◽  
Artifact Reduction ◽  
Metal Artifact ◽  
Metal Artifact Reduction ◽  
Signal Loss ◽  
Resonance Imaging ◽  
Spinal Implants ◽  
Titanium Screws

Background Carbon-reinforced PEEK (C-FRP) implants are non-magnetic and have increasingly been used for the fixation of spinal instabilities. Purpose To compare the effect of different metal artifact reduction (MAR) techniques in magnetic resonance imaging (MRI) on titanium and C-FRP spinal implants. Material and Methods Rod-pedicle screw constructs were mounted on ovine cadaver spine specimens and instrumented with either eight titanium pedicle screws or pedicle screws made of C-FRP and marked with an ultrathin titanium shell. MR scans were performed of each configuration on a 3-T scanner. MR sequences included transaxial conventional T1-weighted turbo spin echo (TSE) sequences, T2-weighted TSE, and short-tau inversion recovery (STIR) sequences and two different MAR-techniques: high-bandwidth (HB) and view-angle-tilting (VAT) with slice encoding for metal artifact correction (SEMAC). Metal artifact degree was assessed by qualitative and quantitative measures. Results There was a much stronger effect on artifact reduction with using C-FRP implants compared to using specific MRI MAR-techniques (screw shank: P < 0.001; screw tulip: P < 0.001; rod: P < 0.001). VAT-SEMAC sequences were able to reduce screw-related signal loss artifacts in constructs with titanium screws to a certain degree. Constructs with C-FRP screws showed less artifact-related implant diameter amplification when compared to constructs with titanium screws ( P < 0.001). Conclusion Constructs with C-FRP screws are associated with significantly less artifacts compared to constructs with titanium screws including dedicated MAR techniques. Artifact-reducing sequences are able to reduce implant-related artifacts. This effect is stronger in constructs with titanium screws than in constructs with C-FRP screws.

Heparin-mediated antibiotic delivery from an electrochemically-aligned collagen sheet

2021 ◽  
pp. 1-12
Author(s):  
Olivia T. Cheng ◽  
Andrew P. Stein ◽  
Eric Babajanian ◽  
Kathryn R. Hoppe ◽  
Shawn Li ◽  
...  
Keyword(s):  
High Performance ◽  
Inhibitory Concentration ◽  
Medical Implants ◽  
Implantable Medical Devices ◽  
Antibiotic Solution ◽  
Inhibition Zones ◽  
Antibiotic Release ◽  
Local Antibiotic ◽  
Antibiotic Delivery

BACKGROUND: Implantable medical devices and hardware are prolific in medicine, but hardware associated infections remain a major issue. OBJECTIVE: To develop and evaluate a novel, biologic antimicrobial coating for medical implants. METHODS: Electrochemically compacted collagen sheets with and without crosslinked heparin were synthesized per protocol developed by our group. Sheets were incubated in antibiotic solution (gentamicin or moxifloxacin) overnight, and in vitro activity was assessed with five-day diffusion assays against Pseudomonas aeruginosa. Antibiotic release overtime from gentamicin infused sheets was determined using in vitro elution and high performance liquid chromatography (HPLC). RESULTS: Collagen-heparin-antibiotic sheets demonstrated larger growth inhibition zones against P. aeruginosa compared to collagen-antibiotic alone sheets. This activity persisted for five days and was not impacted by rinsing sheets prior to evaluation. Rinsed collagen-antibiotic sheets did not show any inhibition zones. Elution of gentamicin from collagen-heparin-gentamicin sheets was slow and remained above the minimal inhibitory concentration for gentamicin sensitive organisms for 29 days. Conversely, collagen-gentamicin sheets eluted their antibiotic payload within 24 hours. Overall, heparin associated sheets demonstrated larger inhibition zones against P. aeruginosa and prolonged elution profile via HPLC. CONCLUSION: We developed a novel, local antibiotic delivery system that could be used to coat medical implants/hardware in the future and reduce post-operative infections.

scholarly journals Metal artifact reduction in computed tomography images based on developed generative adversarial neural network

2021 ◽  
Vol 24 ◽  
pp. 100573
Author(s):  
Goli Khaleghi ◽  
Mohammad Hosntalab ◽  
Mahdi Sadeghi ◽  
Reza Reiazi ◽  
Seied Rabi Mahdavi
Keyword(s):  
Neural Network ◽  
Computed Tomography ◽  
Artifact Reduction ◽  
Metal Artifact ◽  
Metal Artifact Reduction ◽  
Computed Tomography Images

Comparative methods for metal artifact reduction in x-ray CT

2014 ◽  
Author(s):  
Mehrsima Abdoli ◽  
Abolfazl Mehranian ◽  
Angeliki Ailianou ◽  
Minerva Becker ◽  
Habib Zaidi
Keyword(s):  
Comparative Methods ◽  
Artifact Reduction ◽  
Metal Artifact ◽  
Metal Artifact Reduction ◽  
X Ray
Sign in / Sign up

Export Citation Format

Share Document